The invention relates to a system and a method for well completion, control, and monitoring of processes in a reservoir. Uses of the system and method are also disclosed.
In many wells, the hydrocarbon-bearing formation has to be stabilized from collapse of the well bore or cracks around the well bore. Another reason to stabilize a well bore is to reduce the production of fine materials like sand. In order to attain this, the bore is often lined with a perforated steel pipe, and the space between the bore and the pipe may be packed with gravel or proppant particles as described in WO9954592. In addition, different kinds of sand filters (gravel or matrixes) may be placed inside (U.S. Pat. No. 5,893,416, U.S. Pat. No. 5,232,048 and U.S. Pat. No. 5,551,513) the steel pipe a liner.
Usually, during hydrocarbon production a minimum amount of water production (compared to oil or gas) is desirable. This is normally achieved by using techniques to suppress water flooding into the reservoir by altering the production zones or by blocking water breakthrough. For sub sea wells, separation techniques have been attempted to accomplish separation of water produced down in the well bore (downhole), along with reinjection of the produced water. For example, electric powered centrifugal separators have been positioned downhole to generate a fluid separation vortex within the downhole separator. Another solution is to install systems of valves and bypass pipelines in the well bore in order to bypass water production zones (WO9963234). However, such equipment requires power and moving components subject to wear and failure. In U.S. Pat. No. 6,015,011, a downhole separation technique including adjusting the pressure differential across a filter below a packer is described. Other methods proposed to reduce water production in a well includes water sensitive gels (U.S. Pat. No. 5,609,209), water sensitive particles (WO9954592), or microorganisms in porous particles (WO9936667) placed in gravel packing or reservoir fractures. In U.S. Pat. No. 6,015,011, a downhole separation technique involving adjusting the pressure differential across a filter below a packer is described.
In order to optimize the total production of oil and gas from a well, some production zones in a well bore may have to be bypassed or sealed off for a given time. This can be achieved by completing the zones with a cemented liner, which is penetrated mechanically at a later time by intervention. Another solution is to install systems of valves and bypass pipelines in the wellbore in order to bypass given production zones (WO9963234). However, such equipment requires power and moving components subject to wear and failure.
It is also desirable to be able to monitor production and different phenomena, such as local variations in pH, salinity, hydrocarbon composition, temperature, pressure, microorganisms, and the difference between production of formation and/or injection water. A known method for monitoring local flow properties in a well is to lower a logging tool into the well as described in U.S. Pat. No. 4,861,986, U.S. Pat. No. 5,723,781 and U.S. Pat. No. 5,811,807. These tools require power and moving components subject to wear and failure. Another method for monitoring the flow is by chemical tracers injected (U.S. Pat. No. 4,420,565 and U.S. Pat. No. 4,264,329) or placed in solid particle packs placed along the well bore (U.S. Pat. No. 3,991,827 and U.S. Pat. No. 4,008,763). Injection of radioactive isotopes is described in U.S. Pat. No. 5,892,147. NO-C-309884 (belonging to the present applicant) describes methods for chemically immobilizing or integrating tracers in the formation, construction, or filters around the well. The tracers or tracer carriers are chemically intelligently released as a function of specified events, such as oil or water flow rates.
The object of the present invention is to provide a new solution for low cost, fast and simple well or reservoir completion enabling long time monitoring and enhanced production from hydrocarbon wells without any needs for power or moving components.
In accordance with a first aspect, the invention provides a combined prefabricated liner and matrix system comprising an outer perforated pipe system having sufficient strength to work as a liner and/or a sand screener, an inner screen, and a matrix arranged between the outer pipe and inner screen. The combined liner and matrix system constitute a prefabricated liner with predefined properties for fast and simple well and/or reservoir completion, monitoring and control.
The matrix may be porous with a controllable porosity, pore size and pore size distribution, and the porosity and hence the permeability may be automatically affected by the environment, e.g. by water or oil flow, or by manual triggering with specific reagents. These may be added by the use of well known techniques or via injection wells. The matrix is either a bulk form (uniform) type having the same shape as the geometrical volume filled by a monomer/polymer solution prior to polymerization, a package of at least one type of polymer particle, or a combination of polymer particles in a bulk polymer (matrix). The matrix may also comprise an inert or porogen medium or compound. As is known in the art, a porogen is an inert substance (such as a solvent) that occupies a certain volume of a matrix. After a chemical reaction (such as a polymerization reaction) occurs, removal of the substance by, for example, washing and evaporation/drying will create pores in the matrix element. It is also possible to start with an initially compact matrix that becomes porous and permeable as a result of external influence. Both an initially porous and compact matrix may comprise a polymer or chemical compound reacting at the ambient conditions (e.g. temperature, pH, water or triggers), thereby releasing substances chemically bonded or bonded by adsorption to the matrix into the fluid flow.
The matrix may further comprise components that are detectable after release from the matrix, e.g. a chemically intelligent tracer(s) for monitoring, production and/or specific events in the well or reservoir. The tracers may be adsorbed in or chemically bonded to the matrix.
In accordance with a second aspect, the invention provides a method for control and monitoring of processes in a well or reservoir using the combined liner and matrix element system as described above. In particular, the method includes providing the combined liner and matrix element system containing a matrix with certain properties based on reservoir data prior to installation in the reservoir installing the combined liner and matrix element system in the reservoir, and controlling or monitoring the well by interaction with/by means of the matrix.
In accordance with a third aspect of the invention, the above combined liner and matrix system may be used as a combined pipeline in any process equipment, such as reactors, separators and storage tanks.
The liner and matrix element system of the present invention provides a fast and simple method for well completion, control and monitoring of processes preferably to be used in any oil, gas or water production or injection well. In a well, completion parts of the series of elements may be unperforated pipe elements. The matrix may further comprise components inhibiting or preventing any unwanted phenomena, such as bacteria growth or scale formation in the matrix.
The invention may be used in any kind of well bore onshore or offshore. It may also be used for similar purposes in any process equipment.